clear;clc;
n = 20;
% A=rand(n, n);
t1=zeros(30,4);
for i=1:30
B=rand(n, n);B=10*B;
%B=-100*(B*B');
    for k=1:n
        for j=1:n
            B(j,k)=10^B(j,k);
            result = unidrnd(100);
            if result<90
                B(j,k)=0;
          
            end
        end
    end
err= norm(B); p=max(max(abs(B)));q=sum(sum(abs(B)));
t1(i,1)=err;
t1(i,2)=p;
t1(i,3)=err/p;
t1(i,4)=err/q;
end